Title page for ETD etd-01072005-120035

Evaluating the Transit Signal Priority Impacts along the U.S. 1 Corridor in Northern Verginia

Degree

Master of Science

Department

Civil Engineering

Advisory Committee

Advisor Name

Title

Collura, John

Committee Chair

Teordorovic, Dusan

Committee Member

Tignor, Samuel C.

Committee Member

Keywords

Bus Efficiency

Transit Priority

VISSIM

Bus Control Delay

UTDF

NEMA

Date of Defense

2004-12-14

Availability

unrestricted

Abstract

Heavy traffic volumes in peak hours accompanied by closely located signalized intersections and nearside bus stops on U.S. 1, result in congestion and traffic delays that bus transit may be able to alleviate to some extent. The capital investment and operating costs of other transit solutions such as “Bus Rapid Transit” and “Heavy Rail Transit” projects were found to be cost prohibitive compared to bus transit signal priority (TSP) options. Successful implementation of a limited TSP pilot project led local authorities to conclude that TSP should be extended to the full length of the Fairfax Connector bus routes on U.S. 1.

This research focused on testing the impacts of a ten second green extension priority strategy for all the northbound transit buses in the morning peak period at twenty-six signalized intersections along U.S. 1. A micro simulation model VISSIM 3.7 was used to analyze the impacts of TSP.

The simulation analysis indicates that the Fairfax Connector buses might benefit from the

green extension strategy. Overall, improvements of up to 4% for transit travel time savings and 5-13% reduction in control delay for transit vehicles were observed. Considering all side street traffic, the total increase in maximum queue length might be up to 1.23%.

Future research possibilities proposed include the evaluation of different priority strategies such as an early green, red truncation and queue jumps. Impacts of using a dedicated lane for transit buses along with TSP can also be evaluated. Conditional transit signal priority may also include bus occupancy levels and bus latenesses.